Since the issuance of U.S. Pat. No. 1,530,852 to Arthur H. Pitney, Mar. 24, 1925, the postage meter has had a steady evolution. Each meter had a printer included therein on a one-to-one basis, i.e. one metering device and one printing device incorporated into a unit. In postage meters, the need for security is absolute. Such security is applied to postage meters both to the printing portion of the meter and the accounting portion. The reason for the need for absolute security is because a postage meter is printing value, and unless security measures are taken, one would be able to print unauthorized postage, i.e. postage for which no payment is made, thereby defrauding the post office.
Prior art postage meters included an accounting portion, a postal indicia printing portion and a control portion that was coupled to the accounting portion and the printing portion. The accounting portion and the control portion were mechanically secure. They were enclosed in a secure housing so that the critical accounting and control portions can not be tampered with, without rendering such tampering obvious to postal authorities upon inspection.
The printing portion had a printing drum which may incorporate fixed or settable postage. The printing drum was connected to a drive gear which was driven by a first motor. A shutter bar, or other suitable mechanical means coupled thereto prevent rotation of the drive gear, and prevent the printing drum from printing, when the shutter bar is in its closed position. One of the reasons why the shutter bar may prevent the printing drum from printing is that the postage meter does not have sufficient postage to print additional postal indicia. If the postage meter has sufficient postage remaining to print additional postal indicia the control system within the postage meter would release the shutter bar so that it may move to its open position. A solenoid or a second motor was used to move the shutter bar to its open position.
A disadvantage of the foregoing is that two motors or a motor and a solenoid are required to rotate the printing drum and move the shutter bar.